Postoperative pseudomeningocele in a 40-year-old man

Abstract

Postoperative pseudomeningocele is a relatively rare complication of spinal surgery. In addition to patient inconvenience and apprehension, it is also associated with other morbidities, such as headache, lumbar discomfort, and radiculopathy. The word ‘‘pseudo-’’ means that the lesion does not possess of a true meningeal layer lining the cyst wall, which is not a complete sac or cyst and communicates with the arachnoid space. Herein we present a patient who suffered pseudomeningocele formation after lumbar surgery, and was treated successfully with reoperation. This 40-year-old man had a L4–L5 laminectomy, pedicle screw fixation, and intervertebral bone graft fusion for low back pain on March 2004 at a local hospital. During the operation, a cerebrospinal fluid (CSF) leak had occurred. After 1.5 months without symptoms, he came to our hospital for recurrent legs pain and postural headache. On physical examination, there was a palpable fluctuating mass under the previous surgical scar. Magnetic resonance imaging (MRI) revealed an oval-like cystic collection lying posterior to L3–L5 vertebrae. The lesion was about 5 9 8 cm and isointense compared with the CSF signal on both T1and T2-weighted images (Fig. 1). A diagnosis of postoperative pseudomeningocele was highly suspected. Because of failure of conservation treatment, the wound was reopened on February 2005. The entire cyst was visualized and followed deep into the durotomy site. It was fluctuant and tense, and the walls were thin, shiny, and pinkish white. About 100 mL translucence fluid fluxed when incised it. A tiny communication between the dural sac and the pseudomeningocele was seen with the aid of a Valsalva maneuver. After freeing and returning all nerve roots into the intradural space, the defect was sealed. Subcutaneous fat was placed loosely over the site of the dural repair. Paraspinal muscles and overlying fascia were closed in two layers with sutures placed 3–4 mm apart. Drainage tube was not used routinely because we considered that it might lead to the persistence of communication between the intraand extradural spaces and serve as nidus for infection. Postoperatively, he had a good recovery. Postural headache and legs pain were resolved immediately. With a 4-year follow-up, he was still free of symptom. Postoperative pseudomeningocele is described as ‘‘ugly bulging wounds filled with fluid’’ lying dorsal to the thecal canal. It has been postulated occurring mostly by CSF fistula, and these two can be considered to be on a continuum. It may or may not be associated with an arachnoid tear, but a dural tear is necessary for one to form. In this case, it seemed likely, in the presence of a dural defect, that the intradural pressure of the CSF caused a constant outflow of CSF, which kept the tiny defect opening and prevented healing. On the other hand, as a consequence of paravertebral muscle atrophy after previous procedures, there was less soft tissue to tamponade the CSF leak. The resultant paravertebral dead space became filled with CSF and subsequently formed the pseudomeningocele cavity. Although persistent CSF leakage existed, it still took times (more than 1 month) to become large enough to cause the signs and symptoms. C. Liu H.-X. Cai S.-W. Fan (&) Department of Orthopaedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China e-mail: srrshspine@hotmail.com